1. Technical Field
The present invention relates generally to a semiconductor circuit, and more particularly, to a voltage generation circuit.
2. Related Art
An electronic circuit, such as semiconductor memory or a AC-DC converter, uses internal voltages having a variety of voltage levels.
The electronic circuit includes a voltage generation circuit for generating the internal voltages having a variety of voltage levels.
As shown in FIG. 1, the known voltage generation circuit 1 includes a plurality of voltage generation units for generating a plurality of internal voltages.
FIG. 1 has been illustrated as including only first to fourth voltage generation units 10-40 for generating a plurality of internal voltages used in semiconductor memory, for example, first to fourth internal voltages VPP, VPPY, VBB, and VBBW.
The first voltage generation unit 10 includes a VPP oscillator (VPP OSC), a VPP pump, and a VPP detector.
The VPP OSC generates an oscillation signal and supplies it to the VPP pump.
The VPP pump raises the level of the first internal voltage VPP in response to the oscillation signal of the VPP OSC.
The VPP detector generally drives the VPP OSC based on a comparison result between a reference voltage and a first internal voltage VPP. The VPP detector of the first voltage generation unit 10 drives the VPP OSC based on a comparison result between a division voltage having been divided in a proper division ratio and the reference voltage so that the first internal voltage VPP substantially corresponds to the reference voltage.
The VPP detector drives the VPP OSC when the division voltage is lower than the reference voltage and stops the driving of the VPP OSC when the division voltage is above the reference voltage.
The first internal voltage VPP maintains a target level through the repetition of the above-described process.
Each of the second to fourth voltage generation units 20-40 has the same construction as the first voltage generation unit 10 and operates like the first voltage generation unit 10 in order to maintain each of second to fourth internal voltages VPPY, VBB, and VBBW at a target level.
The first to fourth internal voltages VPP, VPPY, VBB, and VBBW of FIG. 1 have different target levels, and thus the reference voltages of the detectors of the first to fourth voltage generation units 10-40 are set to different values.
In the known voltage generation circuit 1, the VPP OSC, the VPPY OSC, the VBB OSC, and the VBBW OSC are provided in the first to fourth voltage generation units 10-40, respectively.
Accordingly, there is a problem in that the configured oscillators increase area and current consumption of the voltage generation circuit.
The problem of increasing area and current consumption becomes more severe as internal voltage increases.